Traveling to Cuba as an American citizen is a huge risk and highly illegal. You can face fines from $3,000 to $10,000! Many people who have gone to Cuba say officials there won't stamp your passport if you ask them not to, but again, you're running the risk of getting caught when you come back to the US. If approached and an official asks you where you've been, you should tell the truth because lying is far worse. I would suggest not going to Cuba!